logging exception in c#

user_767920 0
Viewed 60595

logging exception the code below allows to save the content of an exception in a text file. Here I'm getting only the decription of the error.

but it is not telling me where the exception occured, at which line. Can anyone tell me how can I achive that so I can get even the line number where the exception occured?

#region WriteLogError
/// <summary>
/// Write an error Log in File
/// </summary>
/// <param name="errorMessage"></param>
public void WriteLogError(string errorMessage)
{
  try
  {
    string path = "~/Error/" + DateTime.Today.ToString("dd-mm-yy") + ".txt";
    if (!File.Exists(System.Web.HttpContext.Current.Server.MapPath(path)))
    {
      File.Create(System.Web.HttpContext.Current.Server.MapPath(path))
     .Close();
    }
    using (StreamWriter w = File.AppendText(System.Web.HttpContext.Current.Server.MapPath(path)))
    {
      w.WriteLine("\r\nLog Entry : ");
      w.WriteLine("{0}", DateTime.Now.ToString(CultureInfo.InvariantCulture));
      string err = "Error in: " + System.Web.HttpContext.Current.Request.Url.ToString() 
                 + ". Error Message:" + errorMessage;
      w.WriteLine(err);
      w.WriteLine("__________________________");
      w.Flush();
      w.Close();
    }
  }
  catch (Exception ex)
  {
    WriteLogError(ex.Message);
  }

}

#endregion
logging exception c#
6 Answers

Your solution is pretty good. I went through the same phase
and eventually needed to log more and more (it will come...):

  • logging source location
  • callstack before exception (could be in really different place)
  • all internal exceptions in the same way
  • process id / thread id
  • time (or request ticks)
  • for web - url, http headers, client ip, cookies, web session content
  • some other critical variable values
  • loaded assemblies in memory
  • ...

Preferably in the way that I clicked on the file link where the error occurred,
or clicked on a link in the callstack, and Visual Studio opened up at the appropriate location.
(Of course, all you need to do is *.PDB files, where the paths from the IL code
to your released source in C # are stored.)

So I finally started using this solution:
It exists as a Nuget package - Desharp.
It's for both application types - web and desktop.
See it's Desharp Github documentation. It has many configuration options.

try {
    var myStrangeObj = new { /*... something really mysterious ...*/ };
    throw new Exception("Something really baaaaad with my strange object :-)");
} catch (Exception ex) {

    // store any rendered object in debug.html or debug.log file
    Desharp.Debug.Log(myStrangeObj, Desharp.Level.DEBUG);

    // store exception with all inner exceptions and everything else
    // you need to know later in exceptions.html or exceptions.log file
    Desharp.Debug.Log(ex);
}

It has HTML log formats, every exception in one line,
and from html page you can open in browser, you can click
on file link and go to Visual Studio - it's really addictive!
It's only necessary to install this Desharp editor opener.

See some demos here:

Try to check out any of those repos and log something by the way above.
then you can see logged results into ~/Logs directory. Mostly anything is configurable.

user_70329870

I am only answering for the ask, other people have already mentioned about the code already. If you want the line number to be included in your log you need to include the generated debug files (pdb) in your deployment to the server. If its just your Dev/Test region that is fine but I don't recommend using in production.

user_25172230

Please note that the exception class is serializable. This means that you could easily write the exception class to disk using the builtin XmlSerializer - or use a custom serializer to write to a txt file for example.

Logging to output can ofcourse be done by using ToString() instead of only reading the error message as mentioned in other answers.

Exception class

https://docs.microsoft.com/en-us/dotnet/api/system.exception?redirectedfrom=MSDN&view=netframework-4.7.2

Info about serialization, the act of converting an object to a file on disk and vice versa.

https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/serialization/

user_41228890
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